module syslog3 {
     yang-version 1;
     namespace "http://huawei3.com";
     prefix "sys3";

     include "syslog4";

     identity ipv4-address-family {
         base ref-address-family;
     }

     identity ipv6-address-family {
         base ref-address-family;
     }

    leaf tunnel {
         type identityref {
             base ref-address-family;
         }
    }

    leaf-list network-ref {
        type identityref {
            base ref-address-family;
        }
    }
}